Big Double HP 120s and no ditchable weight

[Archangel]

Hello all:

I am a newbie DIR diver and am now practicing in the pool for MHK's fundamentals class coming up this summer.

I am dialing in my bouyancy with my gimongous #65 Explorer wing and Al OMS BP.

Something just came to mind. I am so heavy (cylinders are 32.44 lbs without the manifold weight full-drops to 14.44 bone dry empty), that I dont wear any ditchable weight.

I usually dive with 18 lbs of lead with one HP 120

I need some advice from you experienced DIR divers.

Do I dive with no ditchable weight?

Should I wear a weight belt and put 4 lbs in and just inflate my DS to compensate?

Do I use my drysuit as a secondary lift bag should my wing fail?

If s**t hits the fan (wing and DS fail), do I cut through my nylon and do a breath hold ascent to the surface?

I thank you for your thoughtful advice in advance,

Tevis

[jb2cool]

Quote: (Originally Posted by Archangel)

If s**t hits the fan (wing and DS fail), do I cut through my nylon and do a breath hold ascent to the surface?

Sure, if you want your lungs to explode. If you need to ascend quickly you need to breathe out (I'm sure you meant that though).

You should aim to have a balanced rig so that even with no additonal bouyancy you are able to swim up against the weight of your gear.

[GLOC]

Quote: (Originally Posted by jb2cool)

Sure, if you want your lungs to explode. If you need to ascend quickly you need to breathe out (I'm sure you meant that though).

You should aim to have a balanced rig so that even with no additonal bouyancy you are able to swim up against the weight of your gear.

As jb said, you need to have a rig which is balanced, which probably means not diving with 120's (17L?) unless there is a very good reason. For normal SAC rates you will probably hit the NDL before you hit the min gas when using a 12L so a 17L is somewhat excessive.

You shouldn't have excess air just to deal with ditchable weight. If your rig is balanced, you shouldn't need to ditch weight to swim against the weight of your rig.

[LauNar]

Yup, you got pretty big tanks if you really are a newbie... I rarely have to turn the dive in OW because of gas with my 2x12 set, and for cave they are more than enough for a while. Actually I'm considering getting a 2x7/200 set for shallow beach dives etc.

This kind of scenario is really more like a thought experiment, you'd have to have really really bad luck to totally flood your wing and DS.

If I had a _total_ loss of buoyancy (wing&DS) in deep OW I'd have to ditch the gear sooner or later, but preferably on the surface...

My options would probably be:
1) ascent/deco using team/buddies for lift, with a flooded DS skipping some deco might be necessary...
2) trying to use SMB for lift
3) swimming ascent and quick ditch of gear when on surface
4) panic and death

...most likely the canister light would have to go first...

It's a good idea to test how it feels to try to stay on the surface with an empty wing/DS and full tanks, with the reg out of mouth.

//LN

[JohnKendall]

Quote: (Originally Posted by Archangel)

Hello all:

I am a newbie DIR diver and am now practicing in the pool for MHK's fundamentals class coming up this summer.

I am dialing in my bouyancy with my gimongous #65 Explorer wing and Al OMS BP.

Something just came to mind. I am so heavy (cylinders are 32.44 lbs without the manifold weight full-drops to 14.44 bone dry empty), that I dont wear any ditchable weight.

I usually dive with 18 lbs of lead with one HP 120

I need some advice from you experienced DIR divers.

Do I dive with no ditchable weight?

Should I wear a weight belt and put 4 lbs in and just inflate my DS to compensate?

Do I use my drysuit as a secondary lift bag should my wing fail?

If s**t hits the fan (wing and DS fail), do I cut through my nylon and do a breath hold ascent to the surface?

I thank you for your thoughtful advice in advance,

Tevis

There is no point in adding extra weight, just to be able to ditch it. You should be weighted so that with empty tanks (30bar/500psi or so) you can hold a 3m stop with no gas in your wing or drysuit.

If you sink, then you need to get rid of some weight, if you float, you need to add some.

This will be explained a lot more in the Fundies course.

HTH
J

[Archangel]

Gimongous amount of thanks for all the replies.

Interesting to note, that I am preparing for deep triox and trimix dives in the far, far future. I read posts on DecoStop, ScubaBoard and here, and noticed as you more experienced divers moved from LP 95s, to 104s, and then HP 130s (sound of cash register. . . cha ching).

I figured that I would save myself the $$$ and just learn on 120s.

Again, I know that it is a newbie thing to do. I have 100 recreational dives under my belt and have made the commitment (hook, line, and sinker) to the DIR tech way, holistic philosophy, and team orientation to diving.

I am gulping the koolaid.

I now ALWAYS dive in a team. I keep in the back of my mind that my "rock bottom" is having enough air in an S-drill (1000 psi at 100 fsw) to get my team mate and I back up to the surface with a completely exhausted cylinder. Diving with more experienced divers (I am a recovering air hog) means terminating the dive at 40 minutes (with a Al 80) instead of longer bottom time for the team.

I have resolved NEVER to go solo diving with doubles on, and yes, JB if I had to do a breath hold, there would be little bubble trails out of my mouth so I dont blow out one of my lungs.

LauNar, I am heeding your advice and tucking a #50 lbs. lift bag behind my BP.

Again thanks guys, question answered and yup, kinda stupid to add weight just to ditch it.

I am looking forward to MHK fine tuning my rig this summer.

A grateful DIR newbie,

Tevis

[Devon Rob]

Hi Archangel,
if I were you I would have a word with your upcoming DIR-F Instructor about equipment. I´m sure he would only be too helpfull regarding your twin 120´s and any other questions you may have regarding appropriate kit for his course.
All the best
Devon Rob

[rjack]

In addition to the balanced rig rationale...

I would make singles out of the 120s and get a smaller set of doubles. LP85s are the best, with HP100s a close second IMO.

Those big doubles are going to wear you out. Back surgery is much more expensive than multiple sets of doubles, which you'll eventually aquire/want anyway.

Richard

[Archangel]

Quote: (Originally Posted by rjack)

In addition to the balanced rig rationale...

I would make singles out of the 120s and get a smaller set of doubles. LP85s are the best, with HP100s a close second IMO.

Those big doubles are going to wear you out. Back surgery is much more expensive than multiple sets of doubles, which you'll eventually aquire/want anyway.

Richard

Richard, thanks man! I am a physician, and KNOW back strain. Remember guys/gals, lift from the hips ALWAYS. Further, I have been diving a single 120 since I have started diving. . . gotten used to it, and the double 120s arent that bad strapped to my back. I am a big guy, 6 feet 225 lbs.

That brings up another question. . . diving doubles on boats, what are your experiences of being accommodated (taking up two bays, or do you get to lay your rig on the deck)?

Further, do the divemasters grab your valves to help you out of the water (back onto the boat) or do you take off your rig, and then drag it back on deck/dive platform?

(guess I am hijacking my own post)

Again, thanks for all the sage advice,

Tevis

[GLOC]

Archangel,

Part of the ethos of DIR is using the right tool for the job. Using a set of twin 120's for anything other than a deep dive is probably not using the right tool for the job. Most dives in the UK are conducted on twin 12's with stages added for deco (or sometimes to extend bottom time) because you will run into bigger deco obligations than should be encountered for open water well before you use up all the air, unless of course you are a real air hog and have a SAC of 30L/min

With regard to boats, I am not sure how things operate in the US, but of the hardboats that I have dived in the UK there isn't a DM as such, there might be a deck hand to help out, sometimes. They are normally there to help you get to and from your seat/kitting up area. We normally use a boat with a lift to make things so much easier, especially if you have been diving a deco schedule. The added weight of a twin 120 set won't help you in any way reducing a hit whilst climbing out the water.

Space of hardboats is sometimes at a premium, sometimes they take it into account, sometimes the boat is designed with technical divers in mind such as the Wey Chieftain III. Talk to the skipper and find out how many divers he is authorised to take out and see if that is single kitted divers or twins; he is the skipper after all!

HTH